Telephone-exchange system



J. L. M QUARRIE TELEPHONE EXCHANGE SYSTEM June 9, 1925.

Filed Feb. 28. 1925 June 9, 1925.

1,541,367 J. MQUARRIE TELEPHONE EXCHANGE SYSTEM Filed Feb. 28, 192-3 8Sheets-Sheet 3 June 9, 1925.

J. L'. M QUARRIE TELEPHONE EXCHANGE SYSTEM 8 Sheets-Sheet 4 Filed Feb,28, 1923 Az y June 9, 1925.

J. L. M QUARRIE TELEPHONE EXCHANGE SYSTEM 8 Sheets-Sheet 5 Filed Feb.28. 1923 QQN mmenfor- James Z. NOmrne W429 June 9, 1925.

J. L. M QUARRIE TELEPHONE EXCHANGE SYSTEM Filed Feb. 28, 1923 8Sheets-Sheet 6 NS J MNM rrrrrrr ii -Mi ,1 r r I mm.

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June 9, 1925.

J. L. M QUARRIE TELEPHONE EXCHANGE SYSTEM 8 Sheets-Sheet 7 Filed Feb.28. 1923 ml enfar v James L/VUua/ m June 9, 1925. 1,541,367

J. L. M QUARRIE TELEPHONE EXCHANGE SYSTEM Filed Feb. 28. 1923 8Sheets-Sheet 8 Fetentcd ame 9, i925.

osira stares; PATENT JAE/LES L. MGQUAREIE, OF NEW] YQEK, N. Y., TWESTERN ELECTRIC GOTJI- PAITZ, INOGBJPOTRATED, NEVZ IQ VIfZ, N. L,lLCQBEOEATION 6F Q' 'W YO; K.

saLEre -Eamenw Y$T M Application filed, Eebruary 28, 1923. Serial No.621,705.

To all .0710721 may, concern. 155, 156., 157, arranged in groups tointer- Be, it known that 1, James L. MCQUARRIE, connect the incomingsubscribers lines with.

a citizen ot the United States, residing at outgoing trunks 130, 131 bymeans of con- New York, in the county of New York, State tactsoperatedby electromagnets. The sub- H of New York, have invented certainnew scribers lines occupyvertical rows of conand usetul Improvements inTelephone-Ex tacts 126., 127, each row comprising a pluchange Systems,of which the tollowing is a rality of lines and each line having accessto full, clear, concise, and exact description. group of horizontallinks. Each of the This invention relates to telephone eX- outgoingtrunks occupies a complete verti- 19 change systems and moreparticularly to cal row 128, 129 having access to all horisystemsemploying automatic switching zontal links in the switch. The groupselecequipment for setting up connections. tor switch 500 is of the sametype compris- The, object oi the invention is to control ing verticalrows of contacts 501, 502, 503,

the selective operations of switches of the 50 i and 505 and horizontallinks 506, 507

15 coordinate type by means of currents of difand 508, there being asmany links and verterent characteristics. tical rows as is necessary forthe given traf A feature of the invention relates to a lie conditions.The incoming trunks appear system in which a plurality oft sources of invertical rows 5-01, 502, etc, each having currents of differingfrequencies are utilized access to all horizontal links. The outgoing 29for recording designations which serve to trunks are divided into groupseach group govern the selective operation of coordinate occupying a l lT W 0%, 05 and switches to establish connections. each trunk havingaccess to a limited num- These and other advantages of the invenber ofhorizontal links. I

tion will become more apparent from the The connector switch 700, alsoof the oo- 25 toll-owing detailed description and also from ordinatetype, consists of vertical rows of the appenoed claims. incoming trunkcontacts 701, 709., each trunk lo 'isidering-the drawing, Figs. 1 to 8,,inhaving access to all horizontal links 705,

clusive, when arranged in the order shown in 7 06, etc. The subscriberslines appearing in Fig. 9, disclose a telephone system embodythe switchmay be divided into groups of ing the principles of the invention and inten, each group comprising a vertical row such detail as to enable afull understanding in the switch, such as rows 703 and 70 i. thereof.Each line has access to a group of horizon Fig. l shows one of a numberof subscribtel links. For example, the subscribers line linesterminating in a line switch of the 720 appears in the row 70% and isaccessible 35 coordinate type together with trunks outto. the horizontallinks 705, 706 and 707. going from the line switch. Fig. 2 showsSimilarly, line 721 lying in the sane group the details of one ot thesetrunks. Fig. 3 is accessible to another group of horizontal illustratesa sender selector of the coordinate links of which two, 708 and 709, areillusl pe employed for associating the different trated.

40 trunks with the common senders. Fig. i The sender selector switch 300is arranged shows one of the common registering and similar to the lineswitch 125. The incomcontrolling senders. Fig. 5 illustrates a first ingcircuits individual to trunks appear in group selector ot' thecoordinate type in vertical rows 3'01, 302, each having access to whichterminate the trunks incoming from a group of links 317, 318, 319, whilethe out- 45 the line switches. Fig. 6 shows controlling going circuitswhich lead to senders appear and testing equipment whereby the sendersin vertical rows 303, 30}, each having access are associated with thegroup selectors and to all of the links in the switch. For examidletrunks selected. Fig. 7 shows a coordiple, the trunk circuit shown infull in Fig. 2 hate connector switch r5 completing conis represented inthe Send r Selec r wi ch 50 nections to subscribers lines. Fig. 8 shows300 in the vertical row 301 and has access to 195 a controlling andtesting equipment assothe two links 318 and 319 and the sender ciablewith the connector switches for testshown in Fig. l is represented inthe vering the condition of called lines. tical row 30% having access toall links.

The preliminary or line switch com? These switches are of the samegeneral no 55 prises a plurality of horizontal link circuitsconstruction and operation as the switch or buttons 101 to 110,inclusive.

shown in the British Patent No. 183,438, issued to Vestern ElectricCompany, Limited, accepted September 6, 1923.

In order that the subscriber may control the selective operations of thecoordinate switches to establish a connection with a wanted line, anumber of register senders are provided at the central office availablefor the subscribers use in making a call.

These senders comprise a plurality of sets cf relay registers 401, 402and 403. Each of these sets represents a digit in the wanted number andwhile only three sets are shown, it will be understood that more may beemployed for larger systems. Furthermore, the sender includes aplurality o-f'tuned relays 400 together wit 1 a number of sources ofalternating current for difierent frequencies. Five of these sources420, 421, 422, 423 and 424 are shown connected to the primary windingsof a transformer. The first five relays 404, 405, 406, etc, of the set400 are each arranged to operate on alternating current of a. particularvalue and of a particular frequency. Similarly,

each of the remaining five relays 410, 411, 412, etc, operate onalternating current of a particular frequency. The values of theserelays are so taken that when alternating current of a particularfrequency is flowing over the line, only one relay will respond theretowhilethe rest of the relays remain inactive. In this manner the relaysmay be selectively operated to register a digit of any value upon theregister relays of the sender.

. At thesubstation of the subscribers line there is provided anoperating set of keys Moreover, there are provided five inductance coils113 to 117, inclusive, and five condensers 118 to 122, inclusive. Thekeys are so wired that by depression of the proper keys any one of thefive sets of inductance coils: and condensers may be connected either tothe tip or ring side of the subscribers line. This gives ten differentalternating current circuits each selected to produce the resonantcondition necessary for the operation of each of the ten difierentalternating current relays 400.

The sources of alternating current being of the same potential but ofdifferent frequencies are inductively connected to the two secondarywindings 430 and 431 of the transformer. Each of these different sourcesof current induce electromotive force of the same frequency in each ofthe windings 430 and 431. These windings, however, are differentiallyarranged and being substantially equal, the result is that the inducedelectromotive forces neutralize each other normally.

A description will now be given of the detailed operation of the systemin the establishment of a call between two subscribers lines. When thesubscriber at staion 100 removes his receiver from the swit-chhook, acircuit is closed from battery through the winding of line relay 136,through the inner contact of cut-off relay 137, conductor 124, conductor158, through the closed contactsof keys 105, 104, etc, thence throughthe switchhook to conductor 159, through the closed contacts of keys106, 107, 108, etc, conductor 160, conductor 123, to ground at the outercontact of relay 137. Relay 136 operates and closes a circuit for therelay 138. Relay 138 completes a circuit for relay 140, which isindividual to the vertical group of lines appearing in the row 12 6 ofthe switch. This circuit may be traced from battery through the,left-hand winding of relay 140, contact of relay 138, innermost backcontact of relay 141, outer right contact of relay 144, to ground. Relay140 operates and closes a holding circuit for itself from batterythrough its right-hand winding and inner right contact, winding of relay141 to ground at the outer right contact of relay 144. Relay 141operates, opens the lefthand winding of relay 140 and closes a circuitfrom battery through the winding of slow-to-release relay 143, middlecontact of relay 141, inner right back contact of relay 144, to ground.Relay 143 operates and closes a substitute holding circuit for re lays140 and 141.

As relays 140 and 141 operate a circuit is closed from battery throughthe winding of vertical magnet 132, outer right front con tact of relay140, inner right front contact of relay 141 to ground at the contact ofre la 143. Magnet 132 prepares the contacts in the vertical row 126 andalso closes a circuit from ground through its contact, conductor 162,left contact of relay 142, left contact of relay 140, right contact ofrelay 136, right-hand winding of relay 139 to battery. Relay 139operates and locks in a circuit from battery through its left-handwinding and left front contact, winding of relay 142 to ground overconductor 162. The relay 139 is individual to the group of horizontallinks containing links 156 and 157 to which the calling subscribers linehas access.

Relay 141 also completes a circuit from ground through its outermostcontact, left contact of relay 144, contact of slow releasing relay 145,brush -148 (assuming the trunk allotter switch 147 to be standing in itssecond position), winding of the vertical trunk magnet 133 to battery.The magnet 133 operates and prepares the contacts in the row 129 foroperation and closes a locking circuit from battery through its windingand left contact, conductor 163, winding of relay 144 to ground at theouter contact of relay 141. Relay 144, however, being shunted by theabove traced circuit does not operate at this time. Magnet 133 alsoestablishes a circuit from ground through its right contact, winding ofrelay 150 to battery. Relay 150 then operates and ground is extendedthrough its contact through the brush 149 of switch 147, contact andWinding of stepping magnet 145., Winding of relay 145 to battery. Thestepping magnet 146 operates in this circuit and advances the switch147' to the terminals representing the next idle trunk outgoing from theswitch 125.. When brush 148 dis engages its second terminal the shuntremoved from relay 144 and this relay operates in series with the magnet133. Relay 14-4 opens the circuit of relay 143 and this latter relaycommences to deenergize.

\Vhile the relay 143 is maintaining its armature, however, a circuit iscompleted from ground through the inner right front contact of relay144, right contact of relay 142, right front contact of relay 139, backcontact of relay 134, horizontal magnet 135 to battery. The magnet 135which is individual to the link 157 effects connection between said linkand the incoming line and also between said link and the idle outgoingtrunk 13,1. Immediately that the connection is efiected a circuit isclosed from battery through the Winding of magnet 135, Winding of relay134, test conductor'of link 157 over the test conductor 154 to ground atthe contact of magnet 133. Relay 134 operates and extends the startthrough to the next horizontal magnet in thegroup. Another circuit isclosed fron'i battery through the Winding of cut-off relay 137 to thetest conductor of link 15? and thence to ground as described. Relay 13'?opens the circuit of relay 136 which dcenergizcs and releases relay 138.

At the time relay 150 operates circuit is established from groundthrough the right contact of magnet 133, contact of relay 150, conductor153, bacl; contact of sloWto-.release relay 203, conductor 213, windingof relay 306 to battery. Relay operates and locks in a circuit frombattery through its Winding and inner left contact, conductor 214 toground at the uppermost back contact of relay 201. Relay 306 closes acircuit from ground through its outer left contact and the Winding ofrelay -7 to battery. Belay 307 operates and a circuit is completed frombattery through the left Winding of relay 308, contact of relay 307,innermost back contact of relay 309 to ground at the outer right contactof relay 312. lzlelay 3G8 operates and locks in a circuit from bat erythrough its right-hand Winding and inner right contact, Winding of relay309 to ground at the outer right contact of relay 312. Relay 309energizes circuit in this circuit and closes a circuit from batterythrough the Winding of sloW-to-release relay 311, middle contact ofrelay 309 to ground at the inner right back contact of relay 312.

A circuit is non closed for the vertical operating magnet 315controlling the row of contacts 301. This circuit leads from batterythrough the Winding of said magnet, outer right front contact of relay303, innermost front contact of relay 309 to ground at the contact ofrelay 311. Magnet 315 operates and prepares the contacts in the row 301. Magnet 315 also closes a circuit from ground through its contact,conductor 323, left contact of relay 310, left con t act of relay 308,outer right contact of relay 306., right-hand Winding of relay 320 tobattery. Relay 320 operates and locks in a circuit from battery throughits lefthand Winding and left contact, Winding of relay 310 to ground atthe contact of magnet 315.

Relay 309 also closes a circuit from ground through its outermostcontact, left contact of relay 312, contact Oi slow relay 313, brush 324(assuming the all otter switch 305 to be standing on its second positionterminal), Winding of magnet 316 to battery. Magnet 316 operates andcloses a circuit from battery through its Winding and contact, conductor325, Winding of relay 3.12 to ground. Relay 312 being shunted by thecircuit above traced does not operate at this time.

Magnet 316, noW operating, prepares the contacts in the vertical row 304and also closes a circuit from ground through its rightcon-tact,conductors 326 and 327, brush 3.28, contact and Winding of stepping innet 314, Winding of relay 313 to battery. Magnet 314 steps the brushes324 and 323 of the allotter switch to the first idle set of terminalsrepresenting an idle register sender. Bela-y 313 holds open the circuitto brush 324 until the switch comes to rest. When the brush 324disengages its second position terminal, the shunt around the Winding ofrelay 312 is opened. and this relay operates in series With magnet 316.

Belay 312 cpensthe circuit of relay 311.

n'hich, being slow. requires an interval of time to release. During thisinterval. a cir-- cult is closed from ground through the inner right"front contact of relay 312, right contact of relay 310, right frontcontact of relay 320, back contact of relay 321 (assuming the linlr 319to be idle), Winding of the operating magnet 322 to battery. lilagnet322 operates the switch to connect the trunk through to the idleregister sender. Immediately that the switch operates, a temporaryholding circuit is closed from battery through the Winding of magnet322. relay 321., through the link circuit and contacts in row 304,conductor 326 to ground at the right contact of magnet 316. Relay 321operates and extends the start wire through to the next horizontal link.

Also, upon the operation of the sender selector 300, a circuit is closedfrom ground through the right contact of magnet 316, conductor 326,through contacts of the switch 300, thence over conductor 329, windingof relay 201 to battery. Relay 201 operates and closes a circuit frombattery through the winding of relay 203 to ground at the uppermostfront contact of said relay 201. Relay 201 also opens the holdingcircuit of relay 306, which, in turn, causes the release of relay 307.Another function of the relay 201 is to extend the tip and ringconductors of the trunk 131 through the sender selector switch 300 tothe selected register sender shown in Fig. 4. This results in theclosure of a circuit which may be traced from ground through thetransformer winding 430, through battery, left-hand winding of relay419, outer contact of relay 439, conductor 451, through the senderselector switch, conductor 331, inner lower front contact of relay 201,conductor 152, thence through the line switch 125 to conductor 124,conductor 158, through keys 105, 104, 103, through the substationapparatus, thence to conductor 159, through keys 106, 107, 108, etc.,conductor 160, conductor 123, thence through the line switch 125,conductor 151, through the inner upper contact of relay 201, conductor330, through the selector switch 300, conductor 450, inner contact ofrelay 439, right-hand winding of relay 419, winding 431 to ground.Direct current flowing in this circuit causes the energization of relay419, which, in turn, causes the energization of slow-to-release relay440.

The aforegoing operations have all taken place in a brief space of timeduring which the slow relays 143 and 311 are still maintaining theirenergization. After the necessary interval, relay 143 releases and opensthe holding circuit of relays 140 and 141. Relay 141 opens the circuitof magnet 132 which releases, causing the release of relays 142 and 139.Relay 141 also causes the re lease of magnet 133 and relay 144. Therertical magnets 132 and 133 are restored and the connection is now heldby the maintained energization of magnet 135. This magnet is heldoperated in a circuit from battery through its winding, winding of relay 134, contacts of the switch 125, conductor 154, contact of relay150, conductor 153 to ground at the contact of relay 203. Relays torswitch is held operated now by the magnet 322 which is energized in acircuit traceable by way of conductor 326 to ground at the contact ofrelay 440. Relay 201 is also held energized by ground on conductor 326.

Assume that the number of the called line 720 is 320. The callingsubscriber accordingly first depresses the No. 3 key 103. The normalcircuit over the calling line is inter rupted and two other circuits areclosed. The first of these circuits may be traced from ground throughthe winding 431 of the transformer, thence through the first five tunedrelays 404, 405, 406 and the associated condensers, and in parallelthrough the right-hand winding of relay 419, inner contact of relay 439to the conductor 450 over the line as above traced to conductor 123,conductor 160, through the keys 110, 109, 103 in series, conductor 159,thence through the contacts of key 103, coil 115, condenser 120, toground. The other circuit closed by the key 103 may be traced fromground through the winding 430, battery, thence through the second fivetuned relays 410, 411, 412 and their associated condensers and inparallel thereto through the left-hand winding of relay 419, outercontact of relay 439 to the conductor 451, thence over the line toconductor 124, impedance coil 112, through the substation apparatus toconductor 159, con tacts of key 103, coil 115 and condenser 120 toground. The characteristics of the first one of these circuits are suchthat the current induced in the secondary of the transformer by thesource 422, for example, is of such a frequency that only the relay 406of the first five relays responds thereto. Due to the characteristics ofthe second circuit above traced, as described in Patent No. 1,337,? 15,issued April 20, 1920 to J. L. McQuarrie, none of the sources of thecurrent 420, 421, 422, etc. induce a current in the secondary of thetransformer sufficient to operate any of the relays of the second groupof five. Hence, but a single relay is operated due to the depression ofkey 103. This relay 406, in energizing, completes a circuit from groundthrough its left contact, conductor 452, brush 436 (position 1), windingof register relay 453 to battery. Relay 453 operates and locks throughits left Contact, conductor 454, to grounded conductor 326. v

The relay 453 represents the digit in the register 401. Although theregisters 401, 402 and 403 are only shown with fire relays each, it isunderstood that there may be as many relays for each register as thenumber of digits to be recorded requires.

The relay 406, in operating, also closes a circuit from ground throughits right contact, conductor 455, winding of stepping magnet 441 tobattery. Magnet 441 ener gizes preparatory to releasing the severalbrushes into their next position when the et is opened. is soon 'elcasesthe button 103, reand the stepping magnet to advance he several \wn'from their as the suits; lay 106 re 441 dce -eases nergizes :hown. inthe k 'econrl position contacts. subscriber depress-es the he 1102 Relay4:05

a closes the circuit of stepping" niagnet when the subscrib r releaseskey in whic 4 advances the 102 beconics deenerr' i-entrol switch inposition 0. I I

' T ,1 the subscribe operates theltey 110 tin the lastd I) run groundtriie transformer, ery, hrough tee 41-11, 4-12 of the second live andensers and also in parallel thereto he left-hand winding of relay 419,contact of relay e 39, conductor 151,

the ring side of the line to coneontac ts of l'rey' 110, reactance 118to grouiid. Another circn ground thjough- .e windugh t of relays 1,

he winnings t "re first tire and their condensers a l thereto throughthe of relay 419', inner coho ductor L50, thence over 1523, re- ,h thesubstation aph tl' lteys 101' to 105, iiiconductor 158, contacts of key110, coir 1125, condei or 116, to groin id. Du to the characteric s olthe first circuit mentioned, as described in the. above mentioned lileQguarrie I nt No. 1,337,715, a currentis induced the: 111 by thesource 42 ofthe necessary frequency to cause the energiaaion of relay458. Hone or" the ot ier relays are operaed. Relay 158 closes a circuitrein ground through left contact, conductor 159, brush e38 (pom ion 3),windingof register relay 4160 to battery. Relay 460 looks to thegrounded conductor 15%. Belay 158 at its right contact closes a circuitfor magnet en which mag-net deenergizes when the subscriber releasestrey 110 and advances the brushes of he control switch into position 1.W

The number now being. recorded on the sender, the next operation totalte place to particular sender with the first up sele-aor switch 500.The association the sender takes place by means of the inulti-contactrelay device 600 comprising a nuniber oit inul ti-contact relays 601,602, each individual to the dilterent coniinon send and servino', whenenergized, to ex tend LIIQ co trol reads from the registers through tothe operating magnets of the selector swi ch lhe relay 601 beingindividual to the particular sender shown, a circuit therefor iscompleted by way of the brush eta-l when the control switch reachesposition 4. v Vi th the relay 601 operated and since register relay isthe. only one operated in the register 401, a circuit is now completedfor the Vertical operating magnet or relay 601, conductor 612-, windiagnet 510 to battery. The magnet es and pares the contacts of all GJQ I UT v n. 1 iv A A trunks in the group. lvlagnet 510 in operating,completes a circuit frorh ground tl-irou'ghits' Contact, winding or themulti- 00; act relay 51 1} to battery. The group of niul'ti-cc tactrelays 518, of which the relay 51% is one, ser i 'e' to associate thetest relays 603 with th" test conductors of the respective trunks in theseveral groups of trunks outgoing from the switch 500.- ,The relay 5 1 1is individual to the group of trunks in the row 305 and, consequently,connects the right-handwindings or the s'e-y'eral test r'elays c0 1,605, some, to the test conductors 01' the seyeral trunks individual to.the group. The left-hand windings of these test relays lead to frontcontacts of relays 518', 519,520 iiidi' ial totl'ie horizontal links506, 508. If any horizontal link is busy, its corresponding relay willbe operated and circuit closed for the lett-l'iai'i'd winding of thecorresponding test relay in the group 6 3.

Assuming that the trunk 521 is the first one to be idle simultaneouslywith the idle condition of its corresponding link 506, relay 605 isaccordingly the first relay to be deehergized while all preceding relays606, 607, etc, are energized either due to the left handiwinding, ,the'right-hand winding. or both windings thereof.

When the relay 51% operates, it coinpletes a circuit from" groundthrough its contact, over conductor 523, the windings of relays 609 and608 in parallel, to battery. Relay 609 being a quick relay operates atonce and conipletes a circuit from ground over its contact, conductor613, contacts of relay 601, conductor 614, through the sender se le-ctorswitch, conductor 332, back contact of S05, conductor 215, winding ofthe Verticaloperating magnet 509 to battery. The magnet 509 operates andprepares the contacts. of the incoming trunk. Magnet 509 completes acircuit from battery throughthe winding of relay 204, conductor 216,inner right front contact of magnet- 509, conductor 217, lowermostcontact of relay '201 to the grounded conductor 158. Relay 204 operatesand locks through its innermost lower contact, conductor 217, thencethrough the contact of relay 201 to the grounded conductor 153. 7

After an interval of time, the slow rela} 608 attracts its armature andacircuit is closed from ground, through the contact thereof, left frontcontacts of relays 607 and 606, lett'back contact of relay 605,conductor 615, left-hand winding of the horizontal operating magnet 515to battery;

Magnet 515 operates and connects the incoinlng trunk through the link506 to the idle outgoing 'trunk 521 in the desired group. 'At theinstant the connection is effected, a circuit is closed from batterythrough the right-hand winding of magnet 515 and in parallelthrough thewinding of 'the grounded test conductor 158.

relay 518, through contacts of the switch to The switch is held operatedunder the control of this circuit and relay 518 applies ground po- 1tential' to the left-hand winding of the test relay 605 to identify thislink as busy when a subsequent connection through the switch.

At the time the control switch of the sender advanced into position 4, acircuit was closed from battery through the winding of slow-'to-operaterelay 445, brush 448 (position 4) to ground. The relay 445 is soconstructed that it requires an interval of time to operate which issufficiently long to permit the'aforegoing operations to transpire. Atthe end of this interval, the relay 445 attracts its armature againstthe contact and circuit is closed from ground through the contact ofsaid relay, contact and winding of the stepping magnet 441 to battery.The magnet 441 interrupts its own circuit and advances the controlswitch out of position 4 and into position 5. While the switch isstanding in position 5, a circuit is closed from battery through thewinding of relay 449, brush 448 to ground on conductor 826. Relay 449operates and locks through its right contact to the grounded conductor326. Due to this advance, the relay 445 and relay 601 becomedeenergized. This results in the release of the vertical operating magisattempted nets 510 and 509 of the selector switch.

Magnet 509, in releasing, closes a circuit from battery, through thewinding of relay 205, middle lower front contact of relay 204, innerback contact of magnet 509, conductor 217, lower contact of relay 201 togrounded conductor 15?}, Relay 205 operates and locks through its leftcontact. The magnet 510 causes the release of themulticontact relay 514,which, in turn, causes the release of relays 608 and 609.

*The next act to take place is the association of the sender with thetesting and controlling equipment in Fig. 8Vwhereby the connector switch700 may be operated in accordance with the last two digits of the callednumber. lVith the control switch in position5, a circuit is closed fromground through the brush 441, conductor 425, winding of multicontactrelay 611 to battery. Relay 611 which is one of a number of relayscomprising the set 610, is individual to the sender shown and serves toconnect that sender through to the controlling equipment shown in Fig.8. With relay 611 operated, a circuit is closed from ground, through theright contact of the register relay. 457, conductor 462, contact ofrelay 611, conductor 616, winding of the vertical operating magnet 712to battery. The magnet 712 controls the vertical row 704 containing thegroup of subscribers lines in which occurs the called line 720. Magnet720 at its contact, coinpletes a circuit for the multi-contact relay 804in the group 801 which is individual to the group of lines containingthe called line and serves to associate the test relays 805, 806, 807,etc., with the test conductors of the lines of such group.

Moreover, a circuit is closed from ground through the right contact ofrelay 46-0 of the register 403, conductor 468, contacts of relay 611,conductor 617, winding of multi-contact relay 803 to battery. Relay 80?;is one of a number of relays in the group 800, each of which representsa different units digit and each of which serve to connect the testrelays 809, 810, 811, etc., with the test conductors of the.corresponding horizontal links in the switch 700 which have access tolines of the different units designations. Relay 803, in operating,closes a circuit from ground through its outer contact, conductor 618,contacts of relay 611, conductor 619, hrough the sender selector switch800, conductor 388, lowermost front contact of relay 204, conductor 207,through contacts of the first selector switch 500, conductor 526,contact of relay 719, winding of the vertical operating magnet 710 tobattery. Relay 803, in operating, connects the windings of ;the testrelays 809, 810, 811, etc., to the cona same time, a test is being madeof su'bsc-ribers line 720. The test ch- 5 purpose may be tracedfronitest conductor of the'llne, over conductor 723, tarough contacts ofrelav 804, conductor 815-, contact of relay 305 (relay 805 havingoperated in parallel with the relay 803'), winding of relay 813 tobattery. i issuiniu-g that the called line is idle, no ground potentialc. ts onthe or, and, conse que-n-tly, the r lay 313 remains deenergized.

At the time relay 803 operated, it closed a circuit for the slow operatnrelay 812. After an interval has expired relay 812 attracts its armatureand a circuit is closed from ground through the back contact of relay813, contact of relay 812, frontcontacts of relay 811 and 810, backcontacts of relay 800, contact of rel y 803, conductor 816-, winding ofhorizontal operating magnet 715 to battery. The magnet 715' operates andextends the incoming trunl': over he idle ii i: 705 to thecalledsubscribefs line 720. ll hen the switch 700 operates, a circuit isclosed from battery, throng 1- the winding of relay 718, contacts of thes'witchTOO, conductor 816, contacts of relay 803', H "not through thecontacts of the test re ground at the back contact of relay 813. Eelay718 operates and locks thro its ...1 1 .s 141 1 s o winding ant. bacrCQILLELCU (,OHC uuo sat,

through contacts the switch 500 to" the grounded conductor The ground onthe test cor 527 is thus extended through the ri nt contact of relay 718to complete a holding circuit for the link magnet 715 and for the relay717. Relay 7-19 operates through a contact of relay "718'. Theconnection: is now held through switches 500 and 700 by means of groundon the conductor 153.

At the time the control switch of the sender moves into pr on aci-rcuitis closed by way of brush M3 for the slow operating relay 440. After thenecessary interval has expired during which the switch 700 has been set,relay 1% attracts its arnia ture and closes a circuit for the steppingmagnet 441. Magnet 4&1 interrupts its own circuit and advances thecontrol switch out of position 5 back into its normal position.

As the control. switch moves back into its normal position, the brushinopens the circuit of relay 611 which releases and dis connects thesender from the controlling equipment of Fig. 8. This causes the releaseof relays 803, 812, 805, i and magnets 710 and 712. With the switch inits normal position, a circuit is closed from ground over conductor 326,brush 4&8, left contact of relay 449, winding of relay 439 to battery.Relay 139 operates and opens the holding circuit of relay 419. Relay noreleases and opens the circuit of relay 4 1-0. After an interval,

relay 140 deenergizes and removing ground froi n conductor permits therelease of relays-L9 and 4530 and also of the register relays 453', an?and- &0.

Upon the removal of ground from the conductor 326, the holding circuitsof magnet 321, relay 322 and relay 201 are opened. The magnet 322 causesthe release of the sender selector switch 300 thereby restoring theregister sender for subsequent use. Relay 201, upon releasing, completesthe ti p' and ring conductors of the trunk 131 through to-the left-handwindings of the repeating coil 200, thus including the callingsubscribers line in series with the repeating coil and battery. Relay202 being included in circuit with the calling line operates andprovides a substitute holding circuitfor the slow relay 203. Relay 201,in releasing, also opens the circuits of relays 204C and 205 whichbecomes deenergized. Relay 204 com-- pletes a circuit for the calleds'ubsc'ribers line in series with the right-hand windings of repeatingcoil 200-.

When the conversation has finished, the calling subscriber replacing hisreceiver on the switchhook opens tlize circuit of the supervisory relay202 which releases the slow relay 203. After an interval, relay 203reinoves ground potential from the conductor 153 whereupon the holdingcircuits of the line switch 125 and the selector switches 500 and 700'-are opened, causing the completeconnection to be restored.

Should the called line 720 be busy at the time it is selected andtested, a ground potential existing on the test conductor thereof ausesthe closure of a circuit by way of conductor 723', through the contactof relay 80%, contact of relay 805, winding of relay 813' to battery.Test relay 813 "operates and when later the slow relay 812' attracts itsarmature, the above traced circuit for the operation of one of thehorizontal magnets is held opened due to the energized conditionof relay813. Thus, if the called line is busy, a connection is not establishedthereto, and the ground potential connected over the front contact ofrelay 813 may serve in any suitable manner to bring about a busy signal,notifying the calling subscriber of the condition of the called line.

For a more detailed understanding of the operation and control ofswitches in a system of this character, reference is made to thepatent'to S. B. Williams, No. 1,517,331, granted December 2, 192%.

What is claimed is 1. The combination in a telephone system of acoordinate selector switch having a plurality of contacts with operablelinks therebetween for establishing connections, a con trollingmechanism for controlling the selective operation of said switch, and aplurality of sources of current of different character for setting saidmechanism.

2. The combination in a telephone system of a plurality of coordinateselector switches having a plurality of incoming and outgoing trunkcontacts with selectively operable links therebetween for establishingconnections, a controlling mechanism for controlling the selectiveoperation of said switches, and a number of sources of current ofdifferent character for setting said mechanism.

3. The combination in a telephone system of a coordinate selector switchhaving a plurality of link circuits for establishing connections, aregister controlling mechanism for controlling the selective operationof said switch and a plurality of sources of current of differentcharacter for setting said register mechanism.

l. The combination in a telephone system of a coordinate selector switchhaving a plurality of links arranged to set up a number of co-existingconnections, a controlling device l'or governing the selective operationof said switch, and a number of sources of current of differentcharacter for setting said controlling device.

5. In a telephone system, a coordinate selector switch comprisingmovable contacts and immovable links therebetween for establishingconnections, a controlling mechanism for governing the selectiveoperation of said switch, a plurality of sources of current of differentcharacter, and means selectively responsive to said currents forvariably setting said controlling mechanism.

6. In a telephone system, coordinate selector switches having sets ofparallel conductors, sets ofmovable contacts associated individuallytherewith and arranged in rows coordinate with said conductors, andmeans for moving said contacts into engagement with said conductors forestablishing connections, a controlling mechanism for governing theselective operation of said switches, and a plurality of sources ofcurrent of different frequencies for setting said mechanism.

7. In a telephone system, a coordinate selector switch having conductorsarranged in open grid, movable contacts associated individuallytherewith and disposed in rows at right angles thereto, and means forinterengaging said conductors and said contacts for establishingconnections between incoming and outgoing lines, a controlling mechanismfor governing the operation of said switch, a plurality of sources ofcurrent of different frequencies, and tuned relays responsive to saidcurrents for variably setting said controlling mechanism.

8. In a telephone system, coordinate se lector switches having parallelconductors, movable contacts, each contact being adjacent to each ofsaid conductors but normally out of engagement therewith, and means formoving said contacts into engagement with said conductors to establishconnections, a controlling mechanism for governing the operation of saidswitches, and a plurality of sources of current of difterent frequencycontrolled by the calling party for setting said mechanism.

9. In atelephone system, incoming lines, outgoing lines, a coordinateselector switch having stationary horizontal links and sets of movablecontacts disposed in vertical rows, each contact of said sets being inpropinquity to each of said links and each of said links being arrangedto engage two of said contacts simultaneously when establishingconnections between said incoming and outgoing lines, a controllingdevice for governing the selective operation of said switch, a number ofsources of current of different frequencies, circuits for said sourcesof current, and means controlled by the calling party to produceresonance in said circuits for the purpose of variably setting saidcontrolling device in accordance with wanted designations.

In witness whereof, I hereunto subscribe my name this 27th day ofFebruary A. D.,

JAMES L. MGQUARRIE.

